I spent a lot of time looking at it today, and to install my head with my A1 studs, using the washers, with a standard-thickness head gasket and without clearancing my valve covers, I need to mill about .24 of an inch from under the head nut. And it's the nut that is hitting the covers, not the stud.
Yet somehow I see all these references of people milling .020" off. Like is that an inside joke, or are they just doing that in addition to clearancing the valve covers or what? Because for these things to fit I'm trying to get over ten times that much milled off.